Method of fracture fixation

ABSTRACT

An external fixator includes a main body and an outrigger for extending over a fractured joint, such as a wrist joint. The main body can be positioned next to a right arm, or flipped over and positioned next to a left arm. The outrigger is attachable to extend either to the left or to the right of the main body, as appropriate. A distal body is removeably connectable to the distal end of the main body, and the distal body can be affixed to bone on the opposite side of the fracture to immobilize the joint where the fracture occurs. The distal body is connected to the main body with an adjustable securement section which provides six degrees of adjustment freedom. The outrigger is attached to the main body through a slide plate in a dual rail configuration which provides two dimensions of adjustment. Fragment pin supports ride in a track of the outrigger, and provide seven degrees of adjustment freedom for directed fixation of fragments at the fracture site. The outrigger is pivotally adjustable relative to the main body, and includes track portions separated by a wrap around angle. The major components of the fixator are molded of plastic. A surgical technique using the fixator includes immobilizing the joint for an initial healing duration and retaining fragment pins in place during a secondary healing duration.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This is a continuation of application Ser. No. 10/233,897, filed Sep. 3,2002, entitled OUTRIGGER FOR BONE FIXATOR, which is acontinuation-in-part from application Ser. No. 10/160,470, filed May 30,2002, entitled FIXATOR WITH OUTRIGGER, incorporated herein by reference,now U.S. Patent No. 6,652,524.

BACKGROUND OF THE INVENTION

This invention relates to external bone fixators for setting fracturesof the human skeleton. In particular, this invention relates to amodular bone fixator assembly for setting fractures of the distal radiusand other bones. This invention improves upon the earlier inventionsdescribed in U.S. Pat. Nos. 6,056,748 and 6,283,964, both entitledMODULAR FIXATOR ASSEMBLY, which are incorporated herein by reference.

The prior art is replete with external bone fixator devices which areused for setting various bone fractures. Many external bone fixatordevices employ transcutaneous pins (e.g., K-wires), stakes, screws orother types of bone fasteners, which are secured in the bone on opposingsides of the fracture. The pins are then secured to an external splintdevice. The external splint device may use various articulations toadjust its position relative to the bone fasteners. During the fixationsurgery, the bone pieces at the fracture may be realigned by thesurgeon. The various articulations in the external splint device mayassist the surgeon in realigning the bone pieces. Once the externalsplint device is secured to the bones and the bone pieces are in thedesired alignment positions, the articulations in the fixator are lockedin place to maintain the bone alignment for a healing duration.

Some of these external bone fixator devices are especially adapted forrepairing fractures of the distal radius. This type of fracture ofteninvolves a fracture site close to the distal head of the radius.Fractures of the distal head of the radius are commonly referred to asColles' fractures. Such fractures may be reduced using bone fastenersset on the distal side of the fracture in the metacarpal bone and bonefasteners set on the proximal side of the fracture in the distal half ofthe radius.

It has been recognized that it is desirable for the wrist to have acertain degree of mobility during the treatment of wrist fractures.However, prior art fixator devices which employ longitudinal tractionapplied by proximal and distal pins generally do not allow motion at thewrist without crossing the joint during the period of fractureimmobilization.

Accordingly, there is a substantial need for improved external fixatordevices. The fixator devices need to be strong, rigid and durable, towithstand any forces or inadvertent blows to which the fracture sight issubjected. The fixator devices must be lightweight, so as to movable bythe patient without extreme difficulty. The fixator devices should bereasonable in manufacturing cost and difficulty. The fixator devicesshould facilitate a wide range of surgical techniques, to permit thesurgeon to best adapt to the particular fracture and to provide the bestmode of healing. In particular, the surgical techniques facilitated bythe fixator device should allow the surgeon to quickly reduce thefracture during surgeon while still providing the support needed duringthe healing duration.

BRIEF SUMMARY OF THE INVENTION

The present invention is a bone fixator using an outrigger, and anoutrigger for such a bone fixator. The main body of the fixator isattached to a long bone on one side of a fracture, and holds theoutrigger so the outrigger is supported over the fracture site. Theoutrigger is preferably attachable to extend either to the left or tothe right of the main body. The outrigger holds fragment pin supportsfor adjustments which are not entirely horizontal relative to the bonefixator/long bone plane. The outrigger thus allows the surgeon greaterflexibility in moving and fixing bone fragment pins as desired relativeto the fracture.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a preferred embodiment of the presentinvention configured for fixation of the right wrist, shown forsimplicity without bone pins and without detail on the heads of the setscrews.

FIG. 2 is a perspective view showing the fixator of FIG. 1, reconfiguredfor fixation of the left wrist and shown attached relative to a leftwrist skeleton, and also depicted using the alternative outrigger ofFIG. 7.

FIG. 3 is an elevational view of the fixator of FIG. 1, shown with setscrews and bolts removed from their respective holes 58, 60, 86, 116 and128.

FIG. 4 is an opposite elevational view of the fixator of FIG. 1, shownwith bolts removed from their respective holes 58, 116 and 128.

FIG. 5 is a bottom (from the proximal) view of the fixator of FIG. 1,shown with bolts removed from their respective holes 58, 60 and with asimplified distal end 18.

FIG. 6 is an end (from the distal) view of the fixator of FIG. 1, shownwithout the rotatable outer clamp member of the distal body.

FIG. 7 is a perspective view showing an alternative outrigger assembly.

FIG. 8 is a perspective view showing a second alternative outrigger.

FIG. 9 is a top view of the outrigger of FIG. 8.

FIG. 10 is a cross-sectional side view of the outrigger of FIGS. 8 and9, taken along line 10-10.

While the above-identified drawing figures set forth preferredembodiments, other embodiments of the present invention are alsocontemplated, some of which are noted in the discussion. In all cases,this disclosure presents the illustrated embodiments of the presentinvention by way of representation and not limitation. Numerous otherminor modifications and embodiments can be devised by those skilled inthe art which fall within the scope and spirit of the principles of thisinvention.

DETAILED DESCRIPTION

A preferred fixator assembly 10 according to the present inventionincludes, as primary components, a splint or distractor device 12, andan outrigger section 14. The distractor device 12 preferably includes aproximal pin clamp member or main body 16 and a distal pin clamp memberor distal body 18. The distal body 18 is attached to the main body 16 bya securable adjustment segment 20. The outrigger section 14 includes anoutrigger 22 shown holding two fragment pin supports 24. The outriggersection 14 is attached to the distractor device 12 with an outriggerattachment 26. The fixator assembly 10 is generally used for repairingfractures of bones, especially fractures of the distal radius 28 asshown in FIG. 2.

The main body 16 is adapted to be fixed to a long bone, which for thepreferred embodiment is the distal third of the radius 28. The main body16 is thus somewhat elongated to reflect the elongated extent of thedistal third of the radius 28. The main body 16 includes structure forsecuring it to proximal bone fasteners 30. In the preferred embodiment,bone fasteners 30 extend through apertures or clamp openings 32 in themain body 16. The clamp openings 32 extend through the main body 16transversely relative to the longitudinal axis 34 of the main body 16.The preferred bone fasteners 30 are 3 mm bone pins or “K-wires”, butmany other types of bone fasteners (such as relatively long, thin bonescrews, etc.) could equivalently be used. The bone pins 30 describedthroughout this application may be affixed into the bone (reamed,driven, compression or distraction, etc.) as taught in U.S. Pat. Nos.6,056,748 and 6,283,964.

During the fixation surgery, the bone pins 30 are preferably insertedthrough the clamp openings 32 and surgically staked into the distalradius 28. The bone fasteners 30 may for instance be directed throughthe main body portion 16 prior to surgical insertion into the radius 28.Alternatively, the bone pins 30 may be staked into the distal radius 28and the main body 16 placed over the staked bone pins 30, but threadingthe bone pins 30 through the clamp openings 32 prior to/duringaffixation to the bone aids in aligning the bone pins 30 relative to theradius 28. Threading the bone pins 30 through the clamp openings 32prior to/during affixation to the bone also aids in spacing and aligningthe bone pins 30 relative to the main body 16.

Once the bone pins 30 are set in the distal radius 28 and advanced asdesired relative to the clamp openings 32 in the main body 16, the bonepins 30 are secured in place relative to the main body 16. For instance,the main body 16 may be positioned relative to the bone pins 30 and theradius 28 such that the main body 16 rests on the soft tissue and skinof the forearm. Alternatively, the surgeon may position the main body 16spaced a short distance from the tissue of the forearm. The preferredstructure to secure the bone pins 30 relative to the main body 16 iswith set screws 36 (shown without detail). The set screws 36 arethreaded into set screw holes 38 which intersect the clamp openings 32.Tightening of the set screws 36 will secure the main body 16 relative tothe surgically staked bone pins 30.

The main body 16 can be positioned in either of at least twoorientations relative to the long bone (radius 28), and the mechanismfor securing the main body 16 to the long bone (radius 28) preferablyaccommodates such multiple orientations. For instance, the main bodyportion 16 of the preferred embodiment includes two pairs of clampopenings (32 a and 32 b, 32 c and 32 d). One pair 32 a, 32 b of theclamp openings 32 extend on one side of the longitudinal axis 34 of themain body 16 (i.e., above the longitudinal axis 34 as shown in FIG. 1),and the opposing pair 32 c, 32 d of the clamp openings 32 extend on theother side of the longitudinal axis 34 (i.e., below the longitudinalaxis 34 as shown in FIG. 1). When positioned for use on the right arm asshown in FIG. 1, the upper set 32 a, 32 b of clamp openings 32 willpreferably be used, with the lower set 32 c, 32 d of clamp openings 32left vacant. Use of the upper set 32 a, 32 b of clamp openings 32 placesthe main body 16 at an elevation relative to the radius 28 which bestpositions the main body 16 relative to intended subsequent placement ofthe distal body 18 and the outrigger 22, and also minimizes the momentsthat the weight of the fixator 10 will place on the radius 28 duringnormal use.

The lower set 32 c, 32 d of clamp openings 32 provide some flexibilityshould the surgeon desire to use the fixator 10 at a higher elevationrelative to the radius 28. However, the primary importance of the lowerset 32 c, 32 d of clamp openings 32 is to provide flexibility so themain body 16 can be equivalently be used on either right or left arms.As shown in FIG. 2, the main body 16 can be flipped for use with theleft arm at the same relative height, simply by utilizing the bone pins30 through the second (now upper) set 32 c, 32 d of clamp openings 32.The preferred embodiment thus includes four clamp openings 32 a, 32 b,32 c, 32 d, with only the upper two (which can be either set dependingupon left or right orientation) being primarily intended for use. Theclamp openings 32 a, 32 b are longitudinally spaced about 1½ inchesapart, about two inches from the distal end of the main body 16. Thisspacing is adequate to support the main body 16 on the radius 28, whilenot coming too close to the typical Colles' fracture site in the radialhead. If desired, additional bone pin clamp openings may be placed inthe main body 16, to give the surgeon additional flexibility inplacement of the bone pins 30. Similarly, if desired the main body maybe made longer, giving the surgeon potential attachment sites into themiddle or proximal thirds of the radius 28. In any orientation, the mainbody 16 is intended to be affixed such that its longitudinal axis 34extends roughly parallel to the longitudinal axis of the radius 28.

The distal pin clamp body 18 of the fixator 10 is used for attachment onthe opposite side of the fracture, and serves as a joint fixation bodyin conjunction with the main body 16 to fix the position of the joint.In the preferred embodiment for use with a Colles' fracture, the distalbody 18 is to be secured to a metacarpal and particularly the secondmetacarpal 40, thereby setting the wrist and preventing the wrist fromflexing during the healing of the Colles' fracture.

Similar to clamp openings 32 of the main body 16, the distal body 18also includes transverse clamp openings 42 for transcutaneous bone pins30 or other bone fasteners. With the distal body 18 of the preferredembodiment, the distal transcutaneous bone pins 30 are surgically setinto the second metacarpal 40. A preferred placement location positionsthe first metacarpal pin 30 about 5 mm distal to the second metacarpaljoint. The distal body 18 is secured relative to the bone pins 30 withset screws 44 (shown in FIGS. 1 and 3 without detail), and therebypositioned such that its longitudinal axis 46 extends roughly parallelto the longitudinal axis of the metacarpal 40. A spacing between thedistal clamp openings 42/distal bone pins 30 of about one inch isappropriate for attachment into the metacarpal 40. Because the distalbody portion 18 does not support the mass and the concomitant potentialmoment of the outrigger 22, a single set of clamp openings 42 areprovided which intersect the longitudinal axis 46 of the distal body 18.If desired however, additional distal clamp openings may be provided togive the surgeon additional options in securing the distal body 18relative to the second bone 40.

The distal body 18 is attached to the main body 16 by the secureableadjustment segment 20. If desired, the distal body 18 can be attachedwith a universal joint allowing pivotal movement of the distal body 18to the main body 16, similar to that taught in U.S. Pat. Nos. 6,056,748and 6,283,964. For some applications, the distal body 18 may be attachedwith a simple pin-type hinge, or may even be permanently securedrelative to the main body 16. However, the preferred secureableadjustment segment 20 includes four degrees of adjustable freedom, eachseparately securable.

As a first degree of freedom, the main body 16 defines a bore 48 whichextends axially therein, and an extension rod 50 is received in the bore48. The extension rod 50 allows the fixator 10 to be lengthened orshortened as appropriate for the particular size of patient beingtreated. Any of several mechanisms can be used so the surgeon cancontrol the extension rod 50. In the preferred embodiment, the extensionrod 50 is externally threaded. A thumb screw 52 is attached on the mainbody 16 such that it is free to rotate. The thumb screw 52 has internalthreads which mate with the external threads of the extension rod 50,such that rotation of the thumb screw 52 advances or retracts theextension rod 50. The longitudinal position of the extension rod 50 islockable via a rod set screw 54 (shown without detail in FIG. 3).

Second and third degrees of adjustment freedom are provided by a yokesection 56, which permits angular adjustment of the distal body 18relative to the main body 16. The yoke section 56 is bolted with ahorizontal bolt 58 (shown in FIG. 1 without detail) to a distal end ofthe extension rod 50 and with a vertical bolt 60 (shown in FIG. 1without detail) to a proximal end of the distal body 18. Each end of theyoke section 56 includes a peak/valley radially-toothed profile whichmates with similarly toothed profiles on the extension rod 50 and distalbody 18. Loosening of the horizontal bolt 58 permits pivoting of theyoke section 56 about a generally horizontal axis 62 defined by thehorizontal bolt 58. Loosening of the vertical bolt 60 permits pivotingof the distal body 18 about a generally vertical axis 64 defined by thevertical bolt 60. Tightening of the horizontal bolt 58 and the verticalbolt 60 secures the distal body 18 at the desired horizontal andvertical angles relative to the longitudinal axis 34 of the main body16. The horizontal and vertical bolts 58, 60 preferably includehexagonal recesses to permit tightening and loosening with an allenwrench. Alternatively, a hexagonal head or a head for a flat or Phillipsscrewdriver, or even thumbscrews may be used.

As a fourth degree of adjustment freedom, the distal body 18 is providedas a central rod 66 (shown in FIG. 6 and in dashed lines in FIG. 5) witha rotatable outer clamp member 68. A set screw 70 (shown without detailin FIG. 1) is provided in a mating threaded hole in the rotatable outerclamp member 68. With the set screw 70 loosened, the outer clamp member68 freely rotates relative to the central rod 66. With the set screw 70tightened, the outer body 68 is secured to the central rod 66. Further,the set screw 70 can be fully loosened to permit the outer clamp member68 to be readily removed from the secureable adjustment segment 20.

If desired, additional degrees of adjustment freedom may be provided bythe securable adjustment segment 20. For instance, the extension rod 50and/or bore 48 may be shaped and configured to permit rotation betweenthe main body 16 and the extension rod 50. The rod set screw 54 couldthen function to secure the position of the extension rod 50 relative tothe main body 16 both longitudinally and rotationally. As anotherexample, the rotatable outer clamp member 68 may be slidable on thecentral rod 66 to permit extension of the distal body 18. The set screw70 would then function to secure the position of the outer clamp member68 relative to the distal body 18 both longitudinally and rotationally.

One purpose of the adjustment freedom provided by the secureableadjustment segment 20 is to maximize the options available to thesurgeon with respect to placement of the bone pins 30 into the secondbone (i.e., in the preferred embodiment, into the second metacarpal 40).In particular, the fixator 10 can be secured both to the radius 28 andto the second metacarpal 40 with the secureable adjustment segment 20fully loose, allowing the surgeon ease of motion to stake the bone pins30 through the fixator 10 and into the bone. A second purpose of theadjustment freedom provided by the secureable adjustment segment 20 isto maximize the options available to the surgeon with respect to thehealing orientation of the bones at the fracture site. After the fixator10 is secured both to the radius 28 and to the second metacarpal 40, thesurgeon can then manipulate the wrist joint to the desired bone healingposition, including the appropriate reduction, distraction, palmerflexion and ulnar deviation. The surgeon can perform the desiredmanipulation of the wrist joint either by applying pressure directly onthe wrist joint itself or with the aid of the fixator 10 by properlymoving the main body 16 and distal body 18 to thereby manipulate thebones. Once the wrist joint is in the desired bone healing position, thebolts 58, 60 and the set screws 44, 54, 70 are fully tightened so thewrist position is rigidly held by the fixator 10.

While traditional fixation can be performed with the distractor device12, the present invention particularly contemplates use for directfragment fixation. Direct fragment fixation is performed with theoutrigger section 14. The outrigger 22 is preferably removably attachedto the main body 16. The outrigger 22 may be attached to the main body16 during surgery, that is, after fixation of the main body 16 to theradius 28 and the distal body 18 to the second metacarpal 40, and aftersecurement of the securable adjustment segment 20. By attaching theoutrigger 22 to the main body 16 after such fixation and securement, thesurgeon has better access to the wrist joint during the fixation andsecurement steps. Alternatively, the outrigger 22 may be attached to themain body 16 prior to surgery or prior to the fixation and adjustmentsteps. As an alternative but less flexible embodiment, the outrigger 22may be permanently secured to the main body 16.

If desired, the outrigger 22 may be attached to the main body 16 by amounting member with thumb gear as taught in U.S. Pat. Nos. 6,056,748and 6,283,964. In the preferred embodiment, however, the outriggersection 14 is attached to the distractor device 12 with a dual sliderailconfiguration provided by the outrigger attachment 26. As best shown inFIGS. 5 and 6, the outrigger attachment 26 includes a rail 72 disposedon the main body 16, a rail 74 disposed on a flange 76 of the outrigger22, and a slide plate 78 which operates in conjunction with the tworails 72, 74. As best shown in FIG. 6, the main body rail 72 is providedon a side of the main body 16 toward the fracture site. While the mainbody rail 72 could extend in any direction, the main body rail 72 in thepreferred embodiment extends longitudinally, parallel to thelongitudinal axis 34 of the main body 16. This orientation provides themain body rail 72 while adding the minimal amount of mass and bulk tothe main body 16. The main body rail 72 mates in sliding engagement witha first slide recess 80 provided on the slide plate 78.

On opposing sides of the main body rail 72, the slide plate 78 abutsrail plate portions 82 of the main body 16 to provide for maximumvertical stability of the outrigger 22. The rail plate portions 82 couldbe co-planar or in parallel planes, but the preferred rail plateportions 82 on the main body 16 extend at angles to each other to bettermatch a generally cylindrical outer profile of the main body 16.

As best shown in FIG. 5, a second slide recess 84 is provided on theopposite side of the slide plate 78, facing away from the main body 16.The second slide recess 84 extends at an angle and preferablyperpendicular relative to the first slide recess 80. The outrigger rail74 on the flange 76 of the outrigger 22 mates in sliding engagement withthe second slide recess 84. On opposing sides of the outrigger rail 74,the slide plate 78 abuts the outrigger flange 76 to provide for maximumhorizontal stability of the outrigger 22. The abutment sides of thepreferred outrigger flange 76 are co-planar.

For both the outrigger rail 74 and the main body rail 72, the preferredshape of the rail is a dovetail having a head and a neck which isnarrower in cross-section than the head. This shape securely limitsmovement of the sliding engagements other than in the slide direction,while still being relatively easy to mold. The preferred length of theslide rails 72, 74 is about 1½ inches, which has been found sufficientto adequately support the outrigger 22 relative to the main body 16while still permitting ½ inch or so of adjustability without significantloss of rigidity.

In the preferred outrigger attachment 26, two distinct modes ofseparability are available. The main body rail 72 is exposed at itsdistal end, and the mating recess 80 of the slide plate 78 is exposed atits proximal end. This allows removal of the slide plate 78 from themain body 16 simply by sliding the slide plate 78 fully in the distaldirection. Attachment of the slide plate 78 to the main body 16 isperformed oppositely, by properly positioning the slide plate 78relative to the main body 16 and sliding the slide plate 78 in theproximal direction.

The outrigger rail 74 is exposed at its anterior end, and the matingrecess 84 of the slide plate 78 is exposed at both its anterior and itsdorsal end. This allows removal of the outrigger 22 from the slide plate78 simply by pulling upward on the outrigger 22. Because the matingrecess 84 of the slide plate 78 is exposed at both ends, the outrigger22 can be removed in the upward direction regardless of the orientationof the slide plate 78, that is, regardless of whether the main body 16is positioned for a right arm with the outrigger 22 extending to theright (FIG. 1) or flipped over and positioned for a left arm with theoutrigger 22 extending to the left (FIG. 2). Attachment of the slideplate 78 to the main body 16 is performed oppositely, by properlypositioning the outrigger 22 relative to the slide plate 78 and pushingdownward.

The two modes of separability give the surgeon flexibility indetermining when and how to attach the outrigger 22 to the main body 16.The slide plate 78 may be attached to the main body 16 before or aftersecuring the main body 16 to the radius 28. Similarly, the outrigger 22may be attached to the slide plate 78 before or after other portions ofthe surgical procedure. The sliding motion also permits infinite fineposition adjustability of the outrigger 22. In particular, the outrigger22 should be placed with 1 cm of clearance over the radial articularsurface.

Releasable securements are provided for securing the rails 72, 74relative to the their respective slide recesses 80, 84. A first setscrew in set screw hole 86, best shown in FIGS. 1 and 3, is used to setthe vertical height of the outrigger 22 relative to the main body 16. Asecond set screw in mating set screw hole 88, best shown in FIGS. 1 and5, is used to fix the longitudinal extent of the main body 16 relativeto the outrigger triangle 22. Both of these set screws 86, 88 are easilyaccessible to the surgeon from the top of the fixator assembly 10. Asimilar set of set screw holes 86, 88 is positioned on the other side ofthe main body 16, for use when the outrigger 22 is attached to extend tothe left over a left arm (FIG. 2).

If desired, the outrigger can be provided as the I-shaped metallicmember shaped as taught in U.S. Pat. Nos. 6,056,748 and 6,283,964. Inthe preferred embodiment, however, the outrigger 22 is provided with arigid triangular shape, best shown in FIGS. 5, 8 and 9. The outrigger 22with this triangular shape projects generally perpendicular to theoutrigger flange 76. The triangular shape is inherently very strong,particularly against deflection from any cantilevered bending stressesplaced on the outrigger 22. The triangular shape generally conforms tothe anatomical configuration of the distal radius 28. In particular, thecoronal anatomy of the radius 28 proceeds from the radial styloidbackward at an angle of about 102° to 110° (depending upon the anatomyof the particular patient) relative to the longitudinal axis of theradius 28. The triangular shape of the outrigger 22 proceeds back from adistal comer 90 at an angle 92 which should be between about 95° and118° relative to the longitudinal axis 34 of the main body 16. The angle92 of the outrigger 22 preferably proceeds at 98° to 115° relative tothe longitudinal axis 34 of the main body 16, more preferably at 102° to110° (i.e., coinciding with the 12-20° angle of the distal head of theradius 28), with a most preferred value being 110°. This angle 92 notonly conforms to the anatomical configuration of the distal radius 28,but also provides an outrigger shape which is inherently strong and wellsupports the cantilevered stresses placed on it by the fragment fixationpin supports 24. That is, a proximal leg 94 cooperates with a distal leg96 to stabilize and strengthen the outrigger 22. Rigidity is enhancedbecause the proximal leg 94 and the distal leg 96 are well separated attheir attachment to the outrigger flange 76. The preferred outriggertriangle 22 extends from the flange 76 for nearly three inches, but isstill sufficiently long because the triangle 22 is over two inches wideincluding a nearly one inch attachment to the flange 76.

The preferred triangular shape only has the distal leg 96 which extendsbackward at an angle of 110°, with the proximal leg 94 extending forwardat an angle of 70°. Only the distal leg 96 is expected to be used forany particular fixation. Of course, when the fixator 10 is used on theopposite arm (from right to left), the direction in which the outrigger22 faces is reversed (from right to left), and the opposite leg 94 ofthe triangular shape becomes the more distal of the two legs 94, 96.

The dual slide rail configuration gives two degrees of freedom inplacing the outrigger 22 with respect to the main body 16. If desired,an additional degree of freedom may be provided as depicted in thealternative outrigger 150 of FIG. 7 and the alternative outrigger 160 ofFIGS. 8-10. The embodiment of FIG. 7 and the embodiment of FIGS. 8-10both include a securable hinge 152. The preferred attachment between thesecurable hinge 152 and the flange 76 is shown only in FIG. 7, butworkers skilled in the art will appreciate that such disclosure appliesequally to the embodiment of FIGS. 8-10. The preferred attachmentbetween the securable hinge 152 and the flange 76 includes a tighteningbolt 154 provided between the base of the triangle 22 and the flange 76.This securable hinge 152 allows pivoting of the triangle 22 relative tothe main body 16, about a horizontal axis 156 parallel to thelongitudinal axis 34 of the main body 16. In the preferred embodiment,the securable hinge 152 allows a range of pivoting from at least +30° toat least −10° relative to horizontal. Thus, a (generally horizontal)reference plane for treatment of the fracture can be defined as a planecontaining the longitudinal axis of the long bone and the longitudinalaxis 34 of the main body 16. The securable hinge 152 pivotably attachesthe outrigger 150, 160 to the main body 16 such that pivotal adjustmentof the outrigger 150, 160 changes an angle of the bone fastener supportmovement direction relative to the reference plane.

The securable hinge 152 pivotably attaches the outrigger 150, 160 to themain body 16 such that the bone fastener support movement direction canbe selected at a greater range of positive angles than negative angles,for two reasons. First, as best shown in FIGS. 7 and 10, the outrigger150, 160 has a lower comer 162 which, depending upon the configurationof the flange 76 and the slide plate 78, may be the point of firstinterference for the outrigger 150, 160 to prevent the outrigger 150,160 from pivoting to further negative angles. If further negative anglesare desired, material may be removed from the lower comer 162 and/or theflange 76 or slide plate 78 (FIG. 7) to allow further rotation. Second,positive angles are generally more desirable than negative anglesbecause positive angles tend to position the outrigger pivoting axis 156closer to the fracture site. Having the outrigger pivoting axis 156close to the fracture site generally minimizes obstruction and makes thesurgical procedure easier. Having the outrigger pivoting axis 156 closeto the fracture site minimizes the distance that the fixator 10 extendsfrom the arm, minimizing the likelihood that the fixator will proveunwieldy or awkward to the patient while wearing the fixator. Having theoutrigger pivoting axis 156 close to the fracture site also generallyminimizes the moments placed upon the main body 16 by forces on thefragment pins 130. That is, angling the outrigger 150, 160 at positiveangles relative to the (horizontal) reference plane creates more of awrap-around relationship between the fixator 10 and the fractured bone,which facilitates both surgical placement and recovery.

As shown in FIG. 7, the tightening bolt 154 has a head with a slot 158for a flat head screwdriver. By tightening of the tightening bolt 154,the rigid securability of the outrigger triangle 22 relative to the mainbody 16 can be maintained at the position ultimately selected by thesurgeon.

The legs 94, 96 of the outrigger 22 define tracks having a slidingrecess 98. As best shown in FIGS. 1 and 4, the sliding recess 98includes opposing lip sections 100, which assist in supporting andholding the fragment pin supports 24. The track configuration of theoutrigger 22 is inherently strong and rigid while still being relativelylightweight.

The preferred sliding recess 98 has an open end 102. This open end 102permits removal of the fragment pin supports 24 from the track 98. Thus,the surgeon can determine how many fragment pin supports 24 should belined up in the track 98 for any particular surgery. If desired, thefirst fragment pin support 24 can be secured in place before the second(or third, etc.) fragment pin support 24 is placed into the track 98.

A most preferred outrigger 160 of the present invention is shown inFIGS. 8-10. Outrigger 160 is formed to have a proximal section 164extending in a first plane, and a distal section 166 extending in asecond plane. A wrap-around angle 168 between the proximal section 164and the distal section 166 can be designed as desired to optimize thedesired movement directions for the fragment pin supports 24. Theproximal section 164 includes a track portion 170 for right hand use anda track portion 172 for left hand use. The distal section 166 includes atrack portion 174 for right hand use and a track portion 176 for lefthand use. Both track portion 170 and 174 for right hand use extend atthe angle 92 relative to the axis 34 of the main body (and the axis ofthe radius). However, because track portion 170 extends in proximalsection 164 and track portion 172 extends in distal section 166, trackportions 170 and 174 are not co-linear, but instead somewhat wrap aroundthe fracture site of the distal radius. With two track portions 170 and174, the desired wrap around angle 168 is less than 50°, and morepreferably greater than about 15° and less than about 45°, and mostpreferably about 35°. Other values could be designed for the wrap aroundangle 168, and particularly shallower values for wrap around angle 168,including shallower wrap around angle values for constructions usingmore than two track portions 170, 174. Track portions 172, 176 for lefthand use similarly benefit from the wrap around angle 168.

The wrap around angle 168 allows the surgeon two defined bone fastenersupport movement directions, each of which is generally parallel to atangent of the distal radius taken at the nearest point. With the wraparound angle 168, two or more fragment pins 130 can be readily directedinto the fracture site from different locations (for instance, atroughly 11 o'clock and 12 o'clock orientations about the radial axis),and readily aligned so each fragment pin 130 is generally asperpendicular as possible to the bone surface at the point of contact.Regardless of the angle of the adjustable hinge 152 selected by thesurgeon, at least one of the track portions 170, 174 is angled relativeto a horizontal reference plane, such that the sliding movement of thefragment pin support 24 therein adjustably changes elevation of thatfragment pin support 24. Thus, the wrap-around angle 168 allows the bonefastener support movement directions to correspond even more closelywith the coronal anatomy of the radius 28. That is, a (generallyhorizontal) reference plane for treatment of the fracture can be definedas a plane containing the longitudinal axis of the long bone and thelongitudinal axis 34 of the main body 16. Because of the wrap-aroundangle 168, the movement direction of at least one of the fragment pinsupports 24 is sloped at an angle relative to the reference plane.

The proximal track portion 170 for right hand use and the distal trackportion 174 for right hand use are separated by a strengthening web 178.Similarly, the proximal track portion 172 for left hand use and thedistal track portion 176 for left hand use are separated by astrengthening web 178. The strengthening webs 178 coincide with the wraparound angle 168 between the proximal portion and the distal portion ofthe outrigger 160. The strengthening webs 178 help the outrigger 160 towithstand forces and moments while maintaining sufficient rigidity atthe wrap around angle 168, a location which otherwise would inherentlyincrease the amount of bending deflection which can be induced in thefixator 10.

The most preferred outrigger 160 has open ends or track openings 180located proximally on the outrigger 160 toward the main body 16. Thetrack openings 180 allows the surgeon to introduce and/or remove thefragment pin support 24 from the proximal track portions 170, 174without moving any fragment pin support 24 which is already in place inthe distal track portions 172, 176. Thus, each proximal track portion170, 174 has its own track opening 180, while each distal track portion172, 176 has its own open end 102.

By having each fragment pin support 24 having a separate opening 102,180, the surgeon has additional flexibility in deciding when to addsecond (and third, etc.) fragment pin supports 24 and their associatedfragment pins 130, and in deciding when to remove those fragment pinsupports 24 and their associated fragment pins 130, without necessarilyadjusting or moving fragment pin supports 24 and their associatedfragment pins 130 which the surgeon desires to keep in place. Forinstance, after a temporary placement or after an initial healingduration, the surgeon could add or remove a proximal fragment pinsupport 24 and its associated fragment pin 130, without moving withoutadjusting or moving either the outrigger 160 or a distal fragment pinsupport 24.

The outrigger 22, 150 or 160 securely and adjustably locates thefragment pin supports 24 as shown in FIGS. 1-6. If desired, the fragmentpin supports may be similar to those described in U.S. Pat. Nos.6,056,748 and 6,283,964. However, the preferred fragment pin supports 24shown herein are molded plastic structures. The preferred fragment pinsupports 24 provide seven degrees of adjustment freedom in locating thefragment pins 130 into the distal radius 28.

As a first degree of adjustment freedom and best shown in FIGS. 1 and 4,each fragment pin support 24 includes a knob bolt 104 which slidablyrides within the track 98. The surgeon can select the desired locationof each knob bolt 104 in the track 98. The knob bolt 104 has a head 106on a threaded shaft section 108. The head 106 mates with the track 98including the opposing lip sections 100, to hold the shaft section 108rigidly upright with respect to the outrigger 22. A tightening nut 110is used on the shaft 108 to releaseably secure the knob bolt 104 at theselected location in the track 98.

If desired, the head 106 of the knob bolt 104 can be elongated orotherwise have flats which mate with the walls of the track 98, to moresecurely hold the knob bolt 104 relative to the outrigger 22. However,as a second degree of adjustment freedom, the head 106 of the knob bolt104 is cylindrical without any flats. This allows the surgeon, while thetightening nut is loose, to rotate the knob bolt 104 about the generallyvertical axis defined by shaft 108 of the knob bolt 104, changing thedirection in which the fragment pin support 24 extends from the track98.

A third degree of adjustment freedom is provided by a pivot arm 112. Thepivot arm 112 includes a fork 114 which mates over the extending end ofthe knob bolt 104. The tines of the fork 114 receive a pivot arm bolt116, with one of the tines threadingly engaging threads of the pivot armbolt 116. Similar to the yoke section 56, the tines of the fork 114 mayhave a peak/valley radially-toothed profile which mates with similarlytoothed profiles on the projecting end of the knob bolt 104.Alternatively, the frictional engagement between flat surfaces of thepivot rod fork 114 and the knob bolt 104 may be sufficient to secure theangular position of the knob bolt 104. Loosening of the pivot arm bolt116 permits pivoting of the pivot arm 112 about a generally horizontalaxis defined by the pivot arm bolt 116. Tightening of the pivot arm bolt116 secures the pivot arm 112 to the knob bolt 104 at a desired angle.The preferred pivot arm 112 has a length of less than an inch, justenough to substantially avoid interference between the fragment pinsupport 24 and the outrigger triangle 22.

Fourth and fifth degrees of adjustment freedom are provided by aconnecting rod 118. The preferred connecting rod 118 has a cylindricalshaft 120 which slides in a cylindrical hole in the extended end of thepivot arm 112. The cylindrical shaft 120 allows the connecting rod 118to be slid upwards and downwards relative to the pivot arm 112, and alsoallows the connecting rod 118 to be pivoted about the axis defined bythe connecting rod shaft 120. A set screw 122 (shown without detail inFIG. 6) is threaded into a threaded set screw hole in the exposed endface of the pivot arm 112. The set screw 122 can be tightened to securethe connecting rod 118 in its desired amount of extension and a desiredrotational position relative to the pivot arm 112. In the preferredembodiment with two fragment pin supports 24, one of the connecting rods118 may be longer than the other, such as having lengths of about 1½inches and 2 inches. The shaft 120 of the connecting rod 118 (which inthe preferred embodiment form the thinnest link of the fixator 10) mustbe sufficiently thick to rigidly support the pin holder 124, such as adiameter of the connecting rod shaft 120 of about ⅕ inch.

A sixth degree of adjustment freedom in the fragment pin support 24 isprovided by the pin holder 124. The pin holder 124 is received betweenthe tines of a fork 126 on the end of the connecting rod 118. The tinesof the connecting rod fork 126 receive a connecting rod bolt 128, withone of the tines threadingly engaging the connecting rod bolt 128.Similar to the yoke section 56 and the pivot arm fork 114, the tines ofthe connecting rod fork 126 may be flat or may have a peak/valleyradially-toothed profile which mates with a similarly toothed profile onthe pin holder 124. Loosening of the connecting rod bolt 128 permitspivoting of the pin holder 124 about a generally horizontal axis definedby the connecting rod bolt 128. Tightening of the connecting rod bolt128 secures the pin holder 124 at the desired angular position.

The seventh degree of adjustment freedom is provided by the connectionbetween the fragment pins 130 and the pin holder 124. The pin holder 124includes at least one through hole 132 for receiving the fragment pin130. A threaded set screw hole intersects the fragment pin through hole132, and a threaded set screw 134 (shown in FIG. 1 without detail) istightenable to secure the fragment pin 130 relative to the pin holder124.

Each of the set screws 36, 44, 54, 70, 86, 88, 122, 134, the pivot armbolt 116 and the connecting rod bolt 128, all shown in the drawingswithout detail, preferably include hexagonal recesses to permittightening and loosening with an allen wrench. Alternatively, ahexagonal head or a head for a flat or Phillips screwdriver, or eventhumbscrews may be used.

The fragment pin holders 124 should have sufficient length to adequatelysupport the fragment pins 130. In the preferred embodiment, the lengthof the pin holder 124 (and the length of the fragment pin through hole132) is over ½ inch. The preferred surgical technique includes settingthe fragment pins 130 through the fragment with the tip of the fragmentpin 130 extending into the healthy, intact radius 28. For the exampledepicted in FIG. 2, two pins 130 are set beginning in the radial styloidand exiting on the opposite intact radial cortex, and a third pin 130secures the dorsal fragment from dorsal and distal to volar andproximal, again exiting in the intact portion of the bone 28. Such pinplacement allows the volar tilt of the wrist to be maintained. Ifnecessary because of the condition of the radius 28, the pin holder 124sufficiently supports the fragment pin 130 such that the tip of thefragment pin 130 may be driven merely into the fragment, with supportsufficient to reduce the fragment being provided by the fragment pinholder 124 without cross-fracture attachment into the radius 28. Thepreferred fragment pins 130 are 0.062 inch diameter wires. The wires canbe drilled free hand or using the pin holders 124 as templates.

In the preferred embodiment, one of the pin holders 124 includes twofragment pin through holes 132. The two holes 132 are separated byroughly ½ inch and extend parallel to each other, to support twofragment pins 130 in a generally parallel spaced relationship. Thesecond pin holder 124 includes a single fragment pin through hole 132.

One of the important advantages of the preferred embodiment is theflexibility it provides the surgeon in the surgical technique used.After the wrist is immobilized with the distractor device 12, thesurgeon may determine where to place fragment pins 130 and how manyfragment pins 130 should be used. Wire placement can be varied dependingon fracture configuration and/or surgeon's preference. The fragment pins130 may be driven into the bone fragments either threaded through thepin holder 124 or even before the fragment pin supports 24 are placedinto the outrigger track 98. After the fragment pins 130 are positionedby the surgeon, the various degrees of adjustment freedom can each betightened to secure the position of the fragments relative to theoutrigger 22, and via the main body 16 relative to the radius 28.

Further, movement of the wrist joint during healing is an important partof the healing process. The present invention contemplates fixation ofthe fragment pins 130 even after the distal body 18 is removed from thesecond metacarpal 40. That is, one preferred surgical technique for thepresent invention involves two separate healing durations. In the firsthealing duration, the fixator 10 is secured to the distal radius 28, tothe second metacarpal 40, and to the bone fragments. Once the bonefragments begin to heal, some stress on the joint is beneficial topromote additional healing and faster bone growth. After an initialhealing duration when the surgeon is confident that fracture stabilityexists, a wrist-release surgery is performed, in which the metacarpalpins 30 are removed from the metacarpal 40 and the distal body 18 isremoved from the main body 16. After the wrist release surgery, thepatient can attain at least a limited degree of wrist flexation, whichimproves the secondary healing. The fragment pins 130 still hold thefragments in place to ensure that the wrist is not refractured duringthis secondary healing. After a secondary healing duration, a thirdsurgery is performed to fully remove the external fixator 10.

Another important advantage of the preferred embodiment is the range ofmaterials which can be used. The preferred embodiment is designed tohandle stresses of the Colles' fracture fixation by using a plasticmaterial. The plastic material used is significantly lighter than metalstraditionally used for fixators. The plastic material used, togetherwith the sizes and shapes discussed herein, allows the fixator 10 to besufficiently rigid without permitting the degree of bending which isinherently possible in most metal fixation structures. The preferredmaterial for the preferred embodiment is a high density plastic,partially glass filled. Because this plastic material is notsufficiently strong to penetrate bone (and for FDA approval reasons),traditional metal bone pins 30 are used, but the remaining parts can allbe molded of plastic. In particular, the main body 16, the distal body18, the secureable adjustment segment 20, the slide plate 78, theoutrigger 22 and the fragment pin supports 24 are all formed of plastic.As a moldable material, manufacture of the fixator 10 can be made lessexpensive. If desired for cost or thread strength reasons, the setscrews 36, 44, 54, 70, 86, 88, 122, 134 and bolts 58, 60, 104, 116, 128described herein may be formed as traditional metal structures as well.The preferred material is an ULTEM 1000, 20% glass bead filled plastic,which is an engineered high density poly-ether-imide (PEI) plasticsuitable for orthopaedic devices and available from GE Plastics. Othersuitable plastic materials might include poly-phenyl-sul-fone (PPSU)(e.g. Amoco Radel R), polysulfone (PSU) (e.g. Amoco Udel P),polyaryletherketone (PAEK) (e.g. BASF Ultrapek), liquid crystal polymer(LCP) (e.g. Vectra); and polyketone (e.g. Amoco Kadel E).

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention. As one example, while the preferredembodiment has been described as having a “main” body and a “distal”body, for certain applications it may be desired to heal the joint byhaving the outrigger 22 supported by the bones distal of the fracture.In the case of a Colles' fracture, this would include attaching the mainbody 16 to the second metacarpal 40 and attaching the “distal” body tothe radius 28. The relative dimension and sizes of the “main” body andthe “distal” body would be adjusted accordingly. Thus a worker skilledin the art will appreciate that the term “distal” is used as a matter ofconvenience and does not necessarily indicate the orientation of thefixator 10 with respect to the fracture. Similarly, the term“horizontal” has been used as a reference direction associated with agenerally horizontal, palm down orientation of the patient's arm/hand,i.e., with the radius and the ulna both at the same height andhorizontal. Workers skilled in the art will appreciate that thisreference direction will change when the orientation of the patient'shand or arm changes. As another example, while the preferred embodimentis intended for Colles' fractures, the invention could be in manyrespects equivalently applied to fractures of other long bones, such asthe proximal radius, and either proximal or distal ends of the ulna,tibia, fibula, humerus, or femur.

1. A method of repairing a fractured joint adjacent a long bone,comprising: performing a fixation surgery comprising: placing aplurality of long bone pins of an external fixator assembly transverselyinto a long bone proximally of the fracture, the external fixatorassembly comprising: a support structure extending generally parallel tothe long bone and perpendicular to the long bone pins, the supportstructure having a proximal section which releasably holds the pluralityof long bone pins, the support structure having a mid-section and adistal section; an outrigger extending generally transversely from themid-section of the support structure, the outrigger having at least onefragment pin releasably attachable thereto; and a plurality of distalbone pins releasably held by the distal section of the supportstructure; securing the long bone pins relative to the supportstructure, thereby fixing the support structure relative to the longbone; placing the plurality of distal bone pins transversely into adistal bone; securing the distal bone pins relative to the supportstructure, such that the external fixator assembly fixes the distal bonerelative to the long bone; placing the fragment pin into a radial bonefragment; and securing the fragment pin relative to the outrigger; afteran initial healing duration, performing a joint-release surgery,comprising: removing the distal bone pins from the distal bone, therebypermitting at least a limited degree of joint flexation; and after asecondary healing duration, performing an external fixator removalsurgery, comprising: removing the long bone pins from the long bone; andremoving the fragment pin from the healed fragment.
 2. The method ofclaim 1, further comprising: at the time of the joint-release surgery,removing the distal section of the support structure from the proximalsection and mid-section of the support structure.
 3. The method of claim1, wherein the proximal section and mid-section of the support structureare provided by a main body, and wherein the distal section is pivotallyattached to the mid-section to permit pivoting of the distal sectionrelative to the main body, wherein the act of securing the distal bonepins relative to the support structure comprises: securing the distalsection of the support structure relative to the main body.
 4. Themethod of claim 3, wherein the long bone is a radius and the distal boneis a metacarpal, wherein the distal section when unsecured pivotsrelative to the main body at least commensurate with anatomical pivotingof the metacarpal relative to the radius.
 5. A method of repairing afracture in or adjacent a long bone and at a joint, which fractureproduces a bone fragment either partly or completely detached from thelong bone, comprising: performing a joint and fracture fixation surgerycomprising: securing a main body of an external fixator assembly suchthat it extends generally parallel to the long bone external to thepatient's tissue, the external fixator assembly further comprising anoutrigger which extends from the main body generally transversely overthe fracture external to the patient's tissue, and a distal body whichextends distally from the main body external to the patient's tissue;placing a fragment pin into the bone fragment, and using the outriggerto secure the fragment pin relative to the main body; securing thedistal body of the external fixator assembly relative to a bone oppositethe joint from the long bone, to thereby restrict movement of the joint;after an initial healing duration with the joint and fracture fixedrelative to the long bone by the external fixator assembly, releasingthe distal body, thereby permitting at least a limited degree of jointflexation, while leaving the fragment pin supported by the main body andoutrigger relative to the long bone; and after a secondary healingduration during which joint flexation occurs, removing the main body andthe fragment pin from the long bone.
 6. The method of claim 5, whereinthe distal body of the external fixator is connected to the main bodywith a securable adjustment segment, the securable adjustment segmenthaving an unsecured state allowing movement of the distal body relativeto the main body and a secured state preventing movement of the distalbody relative to the main body such that the external fixator securesthe joint in a fixed position, and further comprising: attaching themain body to the long bone with the securable adjustment segment in itsunsecured state, and securing the securable adjustment segment into itssecured state for the initial healing duration.
 7. The method of claim5, wherein the outrigger is pivotably connected to the main body, andfurther comprising: securing the outrigger at a selected angularposition relative to the main body for the initial healing duration andthe secondary healing duration.
 8. The method of claim 7, wherein theact of securing the outrigger at a selected angular position occursafter the act of placing the fragment pin into the bone fragment.
 9. Themethod of claim 5, wherein the act of releasing the distal bodycomprises removing the distal body from the main body.
 10. The method ofclaim 5, wherein the act of securing the distal body of the externalfixator assembly to a bone opposite the joint from the long bonecomprises placing pins into the bone and securing the distal body to theplaced pins; and wherein the act of releasing the distal body comprisesremoving the placed pins from the bone.
 11. The method of claim 5,wherein the outrigger is adapted to carry at least one fragment pinsupport; and wherein the method further comprises: changing the numberof fragment pin supports carried by the outrigger without removing theoutrigger from the main body.
 12. The method of claim 11, wherein theact of changing the number of fragment pin supports carried by theoutrigger comprises: attaching a fragment pin support to the outriggerwithout removing the outrigger from the main body, and securing thefragment pin support in a selected location along the outrigger.
 13. Themethod of claim 12, wherein the fragment pin support is slidablyattached to the outrigger, by sliding the fragment pin support from adistal end of the outrigger and in a direction toward the main body. 14.The method of claim 12, wherein the fragment pin support is slidablyattached to the outrigger, by sliding the fragment pin support from aproximal end of the outrigger and in a direction away from the mainbody.
 15. The method of claim 11, wherein the act of changing the numberof fragment pin supports carried by the outrigger comprises: removing afragment pin support from the outrigger without removing the outriggerfrom the main body.
 16. The method of claim 15, wherein the fragment pinsupport is slidably removed from the outrigger, by sliding the fragmentpin support in a direction toward the main body and off a proximal endof the outrigger.
 17. The method of claim 15, wherein the fragment pinsupport is slidably removed from the outrigger, by sliding the fragmentpin support in a direction away from the main body and off a distal endof the outrigger.
 18. The method of claim 5, further comprising:changing the angle at which the outrigger extends from the main body bypivoting the outrigger about an axis generally parallel to the longbone, and securing the outrigger relative to the main body at thechanged angle.
 19. The method of claim 5, wherein the outrigger definesa track having a sliding recess, the method further comprising: addingor removing a bone fastener support from the sliding recess of the trackwith the main body secured relative to the long bone and withoutremoving the outrigger from the main body.
 20. The method of claim 19,wherein the bone fastener support is added to or removed from the trackby longitudinal sliding.